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Synfacts 2008(9): 0921-0921
DOI: 10.1055/s-2008-1078604
DOI: 10.1055/s-2008-1078604
Synthesis of Heterocycles
© Georg Thieme Verlag
Stuttgart ˙ New York
Four-Component Synthesis of 3,4-Dihydro-coumarin Derivatives
A. Shaabani*, E. Soleimani, A. H. Rezayan, A. Sarvary, H. R. Khavasi
Shahid Beheshti University, Tehran, Iran
Further Information
Publication History
Publication Date:
22 August 2008 (online)
Significance
Reported is the synthesis of substituted 3,4-dihydrocoumarin derivatives by a four-component condensation reaction of salicylaldehydes, Meldrum’s acid, alkyl or aryl isocyanides, and aromatic or aliphatic alcohols. The authors propose initial formation of conjugated electron-deficient heterodiene by standard Knoevenagel condensation of 2-hydroxybenzaldehydes and Meldrum’s acid, followed by a [4+1] cycloaddition or a Michael-type addition with isocyanide to afford an iminolactone intermediate. Then, nucleophilic attack of the R²OH component to the activated carbonyl moiety of the intermediate yields the product.